Preparation of lactams from aliphatic .alpha.,.omega.-dinitriles
US5858736A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 17, 1996 |
| Grant date | Jan 12, 1999 |
| Priority date | — |
| Expiry date | May 17, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC12R2001/01
- WIPO fieldBiotechnology
- WIPO sectorChemistry
Abstract
A process for the preparation of five-membered or six-membered ring lactams from aliphatic .alpha.,.omega.-dinitriles has been developed. In the process an aliphatic .alpha.,.omega.-dinitrile is first converted to an ammonium salt of an .omega.-nitrilecarboxylic acid in aqueous solution using a catalyst having an aliphatic nitrilase (EC 3.5.5.7) activity, or a combination of nitrile hydratase (EC 4.2.1.84) and amidase (EC 3.5.1.4) activities. The aimnonium salt of the .omega.-nitrilecarboxylic acid is then converted directly to the corresponding lactam by hydrogenation in aqueous solution, without isolation of the intermediate .omega.-nitrilecarboxylic acid or .omega.-monocarboxylic acid. When the aliphatic .alpha.,.omega.-dinitrile is also unsymmetrically substituted at the .alpha.-carbon atom, the nitrilase produces the .omega.-nitrilecarboxylic acid ammonium salt resulting from hydrolysis of the .omega.-nitrile group with greater than 98% regioselectivity, thereby producing only one of the two possible lactam products during the subsequent hydrogenation. A heat-treatment process to select for desirable regioselective nitrilase or nitrile hydratase activities while destroying und…
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